textproduct: Quad Cities

KEY MESSAGES

- Unseasonably cool temperatures persist through the weekend. Lows dipping into the low 30s tonight and even slightly colder on Sunday night will bring the potential for frost/freeze, especially across our northern zones.

- Area rivers remain on the rise from recent heavy rainfall. Refer to the hydro section below for more details.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 1238 PM CDT Sat Apr 18 2026

The surface cold front has fully departed the region, sweeping the last remnants of any precipitation far eastward. Strong low- level cold air advection (CAA) is well underway behind the boundary. Forecast soundings depict deep boundary layer mixing tapping into a robust west-northwesterly flow aloft yielding sustained winds of 15-25 mph with gusts frequently reaching 25-35 mph with isolated potential for gusts up toward 40 mph. High temperatures this afternoon will top out roughly 10-15 degrees below climatological normals for this point in April, struggling to reach the upper 40s across the north and the low- to-mid 50s for southern locations.

For tonight, as the parent mid-level longwave trough rotates through the Great Lakes, a persistent MSLP gradient will prevent the boundary layer from fully decoupling. As a result, west- northwest winds will remain slightly elevated overnight at roughly 5-15 mph. Residual amounts of low-level moisture and weak positive vorticity advection will maintain periods of stratocumulus into the evening and overnight. Despite NBM exceedance probabilities for sub-freezing temperatures hovering around 50-70% along and north of the Highway 30 corridor, the combination of boundary layer mixing and spotty cloud cover renders widespread frost/freeze development as marginal at this time. Lows are forecast to fall into the mid to lower 30s. Isolated frost remains possible but headline issuance will continue to be deferred at this time pending evening observational trends in temperature, wind speeds, as well as extent and height of any cloud cover.

A shortwave feature on the backside of this departing parent trough will sweep through the region from morning through mid- day on Sunday which could generate low chances (10-30% POPs) of light precipitation across north and eastern portions of the forecast area. Steep low-level lapse rates and sufficient moisture aloft near the ice-bearing layer may allow some snow to mix with these rain showers, but with surface temperatures above freezing, impacts from the snow remain very limited to nonexistent. Winds remain gusty out of the northwest into Sunday afternoon and early evening, generally yielding 15-25 mph.

Sunday night bears further assessment for the increased likelihood of frost/freeze headline issuance. This will be the final period of cold temperatures (in the near-term) with a ~1030mb surface high situated overhead come sunrise on Monday before southerly flow and warm air advection kicks in through the early and middle part of the week.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 301 AM CDT Sat Apr 18 2026

The quiet weather pattern looks to continue through at least mid- week next week, with large upper-level ridging progged to build over the Intermountain West region. Ensembles and deterministic global models suggest at least a small chance (20% or less) of showers/isolated storms Tuesday night as a warm front builds across the area. However, this chance of precipitation appears pretty fleeting, so not much impact expected from this. After a cooler than average weekend, temperatures are expected to gradually warm up Monday through Wednesday, increasing to the middle to upper 70s by Wednesday.

Farther out in time, the weather pattern appears to become more active by Thursday and Friday as a longwave upper trough develops over the western CONUS and approaches the area. This far out, there is much uncertainty on the exact timing and coverage of any precipitation, but general appearance of the synoptic pattern suggests a return of thunderstorms, particularly for Friday, as a cold front builds into the area.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 615 PM CDT Sat Apr 18 2026

Winds will subside with sunset as the lower atmosphere decouples. Overnight winds will be 5 to 10 knots under mainly clear skies. There is the potential for frost on un-hangared aircraft. Deep mixing will commence again around 15z/19 with low level mechanical turbulence from gusts up to 25 knots.

HYDROLOGY

Issued at 320 AM CDT Sat Apr 18 2026

Over the past week, multiple rounds of heavy rain have impacted eastern Iowa and northwestern/west-central Illinois. Rainfall amounts have run from 3 to 6 inches; much of this rain fell north of Highway 30.

Due to this heavy rainfall, area rivers are rising in response, especially in the Mississippi, Wapsipinicon, Iowa, Rock, and Cedar river basins. Several spots have already reached minor flood stage, with several forecast to go to moderate flood, especially on the Rock and the mainstem Mississippi downstream of Rock Island LD 15. Additional rainfall should remain limited over the next several days, but any additional rain may exacerbate these river flooding conditions.

Many area rivers are forecast to continue rising over the next several days, so make sure to be aware of impacts from the flooding, including water on roadways or affected local infrastructure and buildings. Motorists should obey barricades and not drive around them. Also, if you encounter a flooded roadway, turn around and find another route to your destination.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.